I need your help. first i explain about my project outline. Our team working a new online project. my project

contains more than 500 pages. Its divide into three layout structure. one is viewing mode. anther one is

configuration layout, last one is parchase layout. viewing layout using fully ajax interface. here all js files(more

than 15 files) compain into one js file. Its size is 850 KB. I have done compress, now its size is 180kb. Its download time average 2 sec. Initiall load time in our home page 7 sec.

firebug moniter After login my homepage Response time:

1. index.php ===> file size : 20kb ===>timeline===>1.5 sec
2. common.css ===> file size : 15kb ===>timeline===>1.8 sec
3. common.js ===> file size : 180kb ===>timeline===>2.3 sec
4. 3 sprint images ===> file size: 70kb ===> timeline===>2 sec

than i added some bottom Script funtion also.

My question is how to reduce the initial load time with in 3 sec? what can i do?
can i splite common.js file in to three layout based file is it currect or not?

how to improve the initial load time?

give Your suggestion.